The diffusion dynamics of a particle in the biased disorder medium is investigated in this paper. Based on the mean first passage time (MFPT) theory, the analytical approximate expression of effective diffusion coefficient of a particle in the biased disorder potential is obtained. The results show that the effective diffusion of a particle in the biased disorder potential is significantly enhanced. We explain the enhancement mechanism by using the wave packet broadening of probability density distribution function. In addition, we propose the concepts of effective kinetic temperature and effective friction, and further find that the effective diffusion behavior of a particle strongly depends on the biased force.